Halloween parties often have spooky themes. A haunted circus theme can have scary clowns, ghosts, undead performers, a creepy twisted freak show or be led by a devil out to trick people into giving him their souls. To further set the mood, the party can also feature creepy, distorted circus music playing in the background and decorated party tables with tasty but gross-looking treats for a "spook-tacular" good time.
A popular haunted circus theme is killer clowns. Killer clown costumes vary greatly, ranging from a cunning sociopath hiding underneath the smiling, friendly guise of a clown to a deadly, murderous alien masquerading as a clown or even a demonic monster like Pennywise the Clown from the horror novel "It" by Stephen King. Give guests scary clown props, like trick flowers that instead of squirting water emit a red liquid that looks like blood. Offer your guests sinister circus treats like cotton candy covered in edible fake blood made with corn syrup, chocolate powder and red food coloring.
Demonic Freak Show
Freak show circus acts often have creepy mutant animals, monstrous people and geeks that eat anything from glass to insects. A haunted circus demonic freak show themed party can have demons from the depths of hell and other sinister supernatural things pretending to be people waiting for the audience to get within arm's reach so that they can eat them. Put up old timey posters for circus freak show attractions in your home. Decorate your rooms so that each room focuses on a different demonic freak or monster. Put the iron-stomached man in your kitchen or dining area, and have him serve treats such as candy that looks like rocks or fake shards of glass made with clear rock candy and edible bugs in suckers. Your party guests could dress up like freak show performers such as a demon lizard man or a mermaid.
A haunted ghost circus can have a ghostly ring leader, zombie tumblers and acrobat artists who died gruesome deaths. Zombie makeup can create realistic-looking injuries with bones protruding from broken necks and arms of dead acrobats and animal tamers. Build PVC cages, and place fake animal props inside. Set the props on a pneumatic lift that is triggered by motion to scare people as they walk by.
Nightmare Traveling Circus
The nightmare traveling circus theme can be inspired by the novel "Something Wicked This Way Comes" by author Ray Bradbury. In the story, a nightmare traveling circus comes to town, led by Mr. Dark, who lures victims into his mirror maze and allows them to live out their secret fantasies before binding them into eternal service to his carnival. Mr. Dark bears a tattoo for every victim he tricks into eternal servitude in his dark carnival. The host of the party could stand at the house entrance and entice visitors to enter the nightmare circus and indulge in their secret desires. Your guests could dress up as evil characters from Bradbury's story, such as the electricity-conducting man, Mr. Electrico, and the Dust Witch. Guests could also dress up as hapless victims of the nightmare traveling circus or the heroes of the tale, Jim Nightshade and Will Halloway. Decorate the rooms of your house with tin-foil covered poster board or cardboard, and turn it into a nightmarish mirror maze like the one in the novel.